Danger-signal for portable electric tools.



No. 854,013. PATENTED MAY 21, 1907 J. I. AYER.

DANGER SIGNAL FOR PORTABLE ELECTRIC TOOLS.

APPLIOATION 11.31) JAILM, 1-907.

UNITED STATES PATENT OFFICE.

JAMES I. AYER, OF OAMBRIDGEPORT, MASSACHUSETTS, ASSIGNOR TO SIM- PLEX ELECTRIC HEATING COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

Specification of Letters Patent.

Patented May 21, 1907.

Application filed January 14, 1907. Serial No. 852.148.

To 0,66 whom it may concern.-

Be it known that I, JAMES I. AYER, a citizen of the United States, residing at CambridgepIort, 1n the county of Middlesex and State of assachusetts, have invented an Improve ment in Danger-Signals for Portable Electrio Tools, ofwhich the following descript1on, 1n connection with the accompanying draw ngs, is a specification, like letters on the drawings representing like parts.

The introduction of electricity for general use in the kitchen and elsewhere for heating almost all kinds of tools and utensils has developed a wide variet of difliculties from the practical standpomt, and amon the most serious and common is the liability of having the tool overheated and ruined by t e carelessness or ignorance of the user;

While my invention is intended for general application to electrically heated tools, I W1 use by way of illustration an electrically heated flatiron, as this will enable me to present the matter in all its phases.

The average servant girl cannot tell as rule whether she has the current turned on or not, and in fact the position of the switchkey does not usually indicate, except as a matter of memory, whether it i's-in on-position or ofl-position. As therefore the current is. silent and cannot be seen, considerable danger results in the applicatlon of electr1c1ty to domestic uses. A flatiron for instance heats more or less slowly and hence the servant cannot be sure that she has the current on without waiting a few moments to see if the flatiron is becoming heated, and on'the other hand as the iron will remain hot after the current is cut off, she is still uncertain whether she has turned the current off or not. Damage to the clothes being ironed and waste of current frequently results. Accordin 1y I have devised a visible signal for electrically heated tools, by which the .user is notifiedvisually at all timeawliether the lpiuligent is (1m or off and whether it is wor ro er y, In invention consistin in locat' p i1 1 the too itself, and preferably j in series with the current passing through the tool, an incandescent lamp, so that it compels the notice of the user whenever the current is turned on. By having the lamp in series with the tool or unit and in the unit itself, the current must necessarily be off if the lamp is out, and the lamp must necessaril glow if the tool or unit is being heated by t e presence of current.

In the accompanying drawings, Figure 1 is a perspective view of an electrically heated fiat iron with my invention applied thereto; and Fig. 2 is a transverse sectional view thereof.

As already stated, I do not intend to restrict my invention to any particular tool or utensil of domestic use, but/for purposes of illustration I have shown and will describe m invention in connection with a flatiron. Al s o I wish it understood that I'use the word tool herein andin the claims to include not only tools pro er, but utensils and appliances of the kind already referred to.

The body portion or heat retaining part 1 of the flatiron shown in the drawings is provided with a chamber-2 above the bottom or smoothing part 3 of the flatiron, which contains a usual resistance or heating wire 4 whose terminals are indicated at the binding posts 5 6. In the cavity 2 I secure a plate 7 of insulation by any suitable means, as by screws 8, containing 'on its upper side a socket piece 9 for receiving a lamp 10 contained 1n an opening or recess 11 in the top of the flatiron. On 1ts under side the insulation late 7 carries two metal blocks 12, 13, said Yam'p and blocks being provided with any suitable means for electrical connection, the lamp being herein shown as provided with pins 14, 15, passing through the insulation plate 7 into retaimn other-holding means in the metal blocks 12 and 13. From the plug 5 a wire 18 passes to the block 13 and is secured by a set-screw 19, and in the o posite end of the block 12 the adjacent on of the resistancewire 4 is secured by a set-screwv 20. The circuit, then, is from the plu 5 throu h the wire 18, block 13, lamp 10, b ock 12, eating wire 4, back to the opposite terminal lug 6;

enever it is desired to use the fiatiron the servant turns on the switch-key in usual manner and it makes no difierence whether she observes carefully the position of the switch-key or not, as there is no necessity of sockets 16, 17 or.

remembering iow she turned it or infact whether it has been turned or not, because the moment the current is actually present -in the fiatiron the lamp 10 will glow, and as has the tool in her hand or is at a distance.

if the current should cease for any reason, the user of the tool is immediately notified by the sudden extinguishment of the lamp.

From a practical-standpoint, my invention is of great importance, as one of the most frequent and serious annoyances to the users and the manufacturers of this kind of apparatus arises from the careless and ignorant handling of the tools, which I have found is largely due to the fact that the servant girl and others who use them do not know or cannot tell when the current is on or off. An

electrically heated flatiron for instance as at present constructed may be left on the table with full current turned on and yet the servant may suppose she turned it off. There is nothing to notify her one way or the other until perhaps the table or the clothes on which the iron may be resting begin to smoulder or burst out in flames. Then, after the disaster has occurred, the servant learns that she unwittingly left the current turned on. One reason for the great number or" accidents of this kind is due to the fact that the only way heretofore of judging as to the presence or absence of current was by the heat in the iron, and as the iron retains the heat for a considerable time after the current has been turned oii, a servant is liable to think the current is still on when it has just been turned oil, because the iron is warm, and therefore she turns the key again, believing that she is turning it on, when in fact she is turning it on again.

In practice I have found that my invention overcomes all these diiiiculties, and although exceedingly simple, it has proved itself to be of inestimable practical value, especially in connection with household appliances, although as already stated, not restricted thereto.

Having described my invention, what 1 claim as new and desire to secure by Letters Patent is,

1. A portable tool, an electric heating circuit contained therein, opposite terminal plugs in said portable tool connected with the heating circuit, an insulating plate and socket piece also in said tool, and an electric visual signal device removably mounted in said socket piece and operativelyconnected with said heating circuit, said si nal device being visible externally of the too for giving visual warning of the presence of current in the tool.

2. An electrically heated tool, an electric heating circuit contained therein, said tool having an internal cavity normally closed against easy access, contact blocks in said cavity insulated from each other and from the'tool,the latter also having an opening in position to be readily seen and sufliciently deep to contain and protect a visual signal device, an electric visual signal device mo unted in said opening and externally removable therefrom, and means for automatically connecting said signal device operatively with said contact blocks and in said heating circuit to enable the signal device to give visual warning of the presenee of current in the tool.

3. An electrically heated tool, containing a recess or chamber, a dpporting plate secured in said chamber, means connected with said plate for supporting a lamp, an opening from the outer side of said tool to said supporting means, an electric lamp in said opening mounted in said'supporting means, and resistance heating wire in said tool connected with said lamp for giving external visual warning when the current is turned on.

4. An electrically heated tool, containing a recess or chamber, a supporting plate se- 

